Last week Verizon announced a new ‘network optimization’ initiative to start throttling data users. Beginning in October, the carrier is going to start slowing the speeds of the top 5% of its unlimited LTE customers when they’re connected to a busy cell site.

Obviously, VZW subscribers weren’t very happy with the news, and apparently neither was the FCC. Federal Communications Commission Chairman Tom Wheeler sent a letter to Verizon today saying that he was “deeply troubled” by its new throttling plans…

I am deeply troubled by your July 25, 2014 announcement that Verizon Wireless intends to slow down some customers’ data speeds on your 4G LTE network starting in October 2014 .Your website explained that this was an extension of your “Network Optimization” policy, which, according to your website, applies only to customers with unlimited data plans. […]

“Reasonable network management” concerns the technical management of your network; it is not a loophole designed to enhance your revenue streams. It is disturbing to me that Verizon Wireless would base its “network management” on distinctions among its customers’ data plans, rather than on network architecture or technology.

Wheeler also asks that Verizon answer the following:

What is your rationale for treating customers differently based on the type of data plan to which they subscribe, rather than network architecture or technological factors? In particular, please explain your statement that, “If you’re on an unlimited data plan and are concerned that you are in the top 5% of data users, you can switch to a usage-based data plan as customers on usage-based plans are not impacted.”

Why is Verizon Wireless extending speed reductions from its 3G network to its much more efficient 4G LTE network?

How does Verizon Wireless justify this policy consistent with its continuing obligations under the 700 MHz C Block open platform rules, under which Verizon Wireless may not deny, limit, or restrict the ability of end users to download and utilize applications of their choosing on the C Block networks; how can this conduct be justified under the Commission ‘s 2010 Open Internet rules, including the transparency rule that remains in effect?

“We will officially respond to the Chairman’s letter once we have received and reviewed it,” Verizon Wireless said in a statement. “However, what we announced last week was a highly targeted and very limited network optimization effort, only targeting cell cites experiencing high demand. The purpose is to ensure there is capacity for everyone in those limited circumstances, and that high users don’t limit capacity for others.”

Again, this will only affect the top 5% of LTE users—using 4.7GB or more per month—that are still on unlimited data plans, and only when their cell site is experiencing peak usage. Users who don’t want to be throttled can switch to a new usage-based plan.

For what it’s worth, Verizon has been throttling heavy 3G users on unlimited plans for a while now, and other carriers have similar policies in place for their LTE networks. It’ll be interesting to see how Verizon responds to Wheeler, and how this all plays out.